Mr. Chairman and Gentlemen:
There are few things of more importance to the health of a community than good water, and of all classes of people sailors are certainly most sorely tried in that respect. They are compelled to drink water in all parts of the world, and even if they escape absolutely bad water, they must suffer the results of constant change. On board of our men-of-war these evils are partially avoided by a free use of the distilling apparatus; but such use is expensive, and in hot climates, getting up steam for that purpose, not only adds greatly to the discomfort of all on board, but increases the suffering of the sick. Frequently this additional suffering and discomfort might be avoided and coal economized if there were any reliable means on board ship for testing the purity of shore water. At present there are no adequate means furnished for making such tests. In a pamphlet issued from the Naval Laboratory
at New York, entitled "Memoranda to accompany the Naval Test Case," a sufficiently complete and satisfactory method is given for obtaining the degree of hardness as well as the chlorides in waters, but the test suggested for organic matter is the old one of dropping a solution of potassium permanganate into the water until the pink color becomes permanent, and in that form is too crude and incomplete to be of any practical value. It is true that the use of potassium permanganate in water analysis has been advocated by many distinguished chemists, notably by Drs. Miller, Woods and Letheby, and very recently Dr. C. Meymott Tidy, in a paper published in the Journal of the Chemical Society, January 1879, describes a process depending upon the action of potassium permanganate upon organic matter in waters, which he calls the "oxygen process," Without however the numerous and delicate precautions embodied by him in this process the use of potassium permanganate as a test of the organic purity of water is of no value, but is worse than useless if any reliance be placed upon it. In fact, however, no reliance is placed upon it, and our surgeons, appreciating the inadequacy of the means placed at their disposal for testing water, almost invariably recommend, on all stations within the tropics, that no water shall be taken from shore. Under the circumstances such a rule is the only safe one, and yet it is in just these parts of the world, the heat and discomfort of distilling are most felt. But aside from its very great importance in these climates in enabling the surgeon to discover and approve good water, a more accurate water test will be of even greater advantage in other parts of the world in detecting bad water, where the general healthfulness of the climate may have tended to lull suspicion.
The impracticability of setting up a working laboratory on board ship or the complex apparatus for ordinary water analysis is apparent to every one; hence, though the want has been felt by all, little effort has been made to supply it. It would seem, however, that for the new system of water analysis which has recently come into common use, a simple and compact apparatus might be designed suitable for ship board. A plan for such an apparatus, or rather, the suggestion of a plan, for it is by no means complete, I desire to propose to the members of the Institute this evening.
In complete water analysis, the amount and character of the solid contents must be accurately ascertained. On board ship this sort of careful work cannot be done, and fortunately for our purposes, it is not necessary. The great danger is from organic impurity, and water may be sufficiently impure from the presence of organic matter to cause dysentery, typhoid fever and other diseases, and yet be perfectly clear to the eye and pleasant to the taste. Hence, the detection of organic impurities is of the first importance.
While connected with the department of chemistry and explosives at the Torpedo Station, Captain K. R. Breese, then in command, called the attention of Mr. Hill, the chemist of the station, and myself, to the possibility of designing some convenient and simple apparatus for testing water on board ship. The pressure of Mr. Hill's other duties and my own subsequent detachment prevented our giving the subject the attention I could have wished, but I trust I may be able to make the practicability of some plan, either ours or one of a similar character, sufficiently clear to awaken an interest in the subject.
There are three different methods common among chemists for determining the organic matter in water, viz., the ammonia, combustion and oxygen processes. Of these the first, on account of its ease, simplicity, and rapidity, seemed best adapted to the purpose we had in view, which was not an accurate quantitative analysis of the water, but simply a speedy method of judging of its wholesomeness. Hence our efforts were confined to adapting this method for use on ship board with as little labor and as simple and economical apparatus as possible.
The combustion process, commonly called after its inventor. Dr. Frankland, requires an accurate and careful analysis of the water residue after evaporation. This demands a considerable time, special and elaborate apparatus, and great skill in manipulation, and for these reasons, aside from all others, it is impracticable on board ship, where none of the ordinary facilities of a laboratory for delicate work can be expected. The oxygen process, as previously stated, is based upon and is a refinement of the old potassium permanganate method, and though it is possible it might be adapted to use on board ship, it has not yet had sufficient trial by different chemists to warrant its adoption, and it certainly demands more time as well as more delicacy of manipulation than the ammonia process of Wanklyn. This consists, in the words of Wanklyn himself, "in the measurement of the nitrogenous organic matter in waters, by the quantities of ammonia yielded by the destruction of the organic matter." The quantity of ammonia is indicated by the Nessler test. The process requires, 1st, the distillation of the water by itself, and 2nd, its distillation with potassium permanganate and caustic potash in excess. The ammonia produced from the first distillation is called "free ammonia," and is rather "an indication of past contamination": that from the second distillation is called "albuminoid ammonia," and in any appreciable quantity, indicates the actual presence of dangerous organic matter. This process does not require an extensive apparatus or numerous reagents, nor any of the usual laboratory facilities for ignition, drying, weighing, filtering, etc., neither is it necessary that the operator should be an expert chemist. The combustion and oxygen processes are distinctly chemist's processes, while by Wanklyn's method, any intelligent person, having a fair knowledge of the general principles of chemistry, and his reagents all prepared, can, with very little practice, make a determination with sufficient nicety for all ordinary purposes. Still, simple as it is, the ordinary apparatus is too large for use on shipboard, nor would it be convenient to provide a sufficient amount of water for a Liebig condenser.
Before describing the compact apparatus suggested for this purpose, I may, perhaps, be excused for giving a brief outline of the Wanklyn process. (See Water Analysis, Wanklyn, for full particulars.)
A half liter of water is used. This is poured into a clean glass retort, whose beak fits into the tube of a Liebig condenser, to which a supply of water is generally carried by rubber tubing from the sink. The flame of a Bunsen lamp or gas burner being applied to the retort, the water soon begins to boil and distil over. The distillate is collected in glass cylinders marked at 50 c. c. (cubic centimeters) each and reserved for the Nessler test. This consists in dropping 2 c. c. of the Nessler reagent into each 50 c. c. of the distillate. If there is any ammonia present the liquid will assume a brown color, varying in depth according to the amount of ammonia present. The amount of ammonia is found by taking a clean cylinder and dropping into it a certain measured quantity of a standard solution of ammonia, and filling up the cylinder to the 50 c.c. mark with pure distilled water. This is then treated in the same manner with the Nessler reagent and the two cylinders are then placed side by side on a white surface, and their colors compared. This process is continued, with varying quantities of the standard solution, until the imitation is perfect. In practice, the first 50 c. c. is Nesslerised for the free ammonia, and the next 150 c. c. thrown away, experience having shown that they always contain just one third of the amount shown in the first 50 c. c. The distillation is then stopped and 50 c. c. of a solution of potash and potassium permanganate added, after which the distillation is continued, and the succeeding three 50 c. c. of distillate carefully Nesslerised, to obtain the amount of albuminoid ammonia. The standard solution of ammonia is so arranged that each cubic centimeter will represent one part to the million where one liter of water is used, consequently, as the amount of water actually used is but half a liter, the results obtained by the first and second distillations are doubled to obtain the number of parts to the million or milligrams to the liter. Where these show more than fifteen parts of albuminoid ammonia to the million, the water should be rejected. It will be perceived there are no weighings nor tedious dryings and careful ignitions in this process. The calculations are already made and the test consists simply in the careful comparison of colors, and with a little practice, this can be readily done. Many objections have been urged to this method from a scientific standpoint, partly induced, perhaps, by the inordinate claims made for it by some of its advocates, but even its opponents acknowledge that its indications are valuable, while denying the precision of its results.
It may not enable us to say, exactly, how much organic nitrogen there is in the water, but it will enable us to judge, for all practical purposes, whether it be wholesome or not, and that is all we desire. From its ease, convenience, and simplicity it would appear decidedly the most practicable method on board ship, It does not displace any other method: it takes the place, virtually, of nothing. Consequently its adoption does not seem to involve any discussion of its merits compared with those of the other two methods I have mentioned. On this subject the most distinguished experts differ and a most excited controversy has been carried on among them for some time past. This is consequently ground upon which I do not care to tread.
To shorten the Wanklyn process and simplify the necessary apparatus, it is proposed by Mr. Hill to use but 50 c. c. of water. This would require but a small retort; a flask capable of holding 100 c. c. with oval bottom, glass stopper and outlet tube at the neck (see B fig. 1) would probably be the most convenient; this to be held by an ordinary retort holder about fifteen inches high. A spirit lamp will supply the necessary heat. The condenser may be a flask with a glass worm, such as is sometimes made for laboratory use, or as I would prefer, a small copper condenser with a flat, silver lined, angular worm (w fig. 2.) This form of condenser, with a tin lined worm has been patented for the use of druggists, is very small, not much larger than a quart measure, but I have seen it in operation and it does its work rapidly and perfectly. For our purpose it would be better to have the worm silver lined, and the. plating could be done at very little extra cost over the ordinary tin lining. The small amount of sea water necessary for condensing can be supplied through the funnel by an attendant. The Nessler reagent, ammonia and potash solutions should be carefully prepared at the Medical Laboratory, bottled, and put on board ship with the medicinal stores. With the small amount of water used, the quantities of these required would be very much reduced. A four ounce bottle of the Nessler reagent and a liter of each of the other solutions would seem amply sufficient for a cruise. Should the Nessler reagent become exhausted or need renewal, all the necessary materials for preparing it will be found among the ordinary medical stores. If preferred, the Nessler reagent could be put up in separate bulbs, similar to those containing sulphuric acid in the Harvey bolts, each bulb holding the exact amount to be used at one time, that is, about .2 or .25 c.c. of the reagent. This would avoid the necessity of making such small measurements with the pipette.
In addition the following apparatus would be necessary:—
Six (6) small glass cylinders, marked at 5 c. c. each. One (1) graduated burette, to measure the standard solution of ammonia, and a small number of glass rods and tubes. Most of these will be found in the Naval Test Case and the remainder can be added to it without much additional cost and very little increase of size. The most expensive feature of the apparatus is the condenser, and that will cost about five or six dollars.
It will not, of course be necessary to make an organic determination of all water received on board ship, but only when taking it for the first time in any given port, or where there is reason to suspect the character of the shore water, nor will it be necessary, each time, to measure the exact quantity of organic impurity. If the application of the Nessler reagent to the first distillate gives a decided brown color, it will be sufficient to warrant the rejection of the water without continuing the process, as no water, bearing the slightest suspicion of present or past contamination should be received on board ship. The extreme care and exactness required in the examination of water for a permanent supply, do not enter into the question here. If the water from one well or cistern is not perfectly satisfactory, it can easily be procured from another, if that is still unsatisfactory, the distilling apparatus always remains as a last resort. There is therefore no reason why water having the slightest taint of suspicion should be received. This, as you will readily perceive, simplifies very much the task of the examiner.
The time required for such an examination would be small. I have made a careful determination, by the Wanklyn process, using a half liter of water, in about two hours, including the time required to set up the apparatus. With 50 c. c. of water and the ship apparatus, it ought not to take more than three quarters of an hour, and for the incomplete tests, which would be all that would be necessary with positively bad water, twenty minutes ought to be sufficient. The pure water required for the purpose of comparison should be previously distilled with the same apparatus from very pure spring water, if possible, and kept in bottles for use when required.
The organic impurity of water is of the first importance, and with a satisfactory test for that, one may rest content; still, it sometimes happens that organically pure water will contain such a large quantity of dissolved and suspended matter, as to be unfit for cooking and drinking purposes. This is the case with very hard water. It is a thumb rule that the total solids should not exceed forty grains to the gallon, and, should it be desired, this total amount could be very easily obtained, (though somewhat roughly, perhaps,) by carefully evaporating 70 c. c. of the water in a porcelain or platinum dish, which had been previously weighed, and then reweighing the dish and residue after evaporation, the difference in weight in milligrams being the number of grains of solid contents to the gallon. This is, of course, common practice, and I merely suggest it as a simple additional test, requiring no apparatus excepting a small water bath, an evaporating dish and the apothecary's scales. In itself, it is, of course, of little importance compared with the previous tests for organic impurity, still the process of evaporation may give some valuable indications as to the organic condition of the water, as most impure waters on evaporation to dryness, give off an offensive odor, and it seems to me the Surgeon should have the apparatus for making this examination, should he consider it necessary.
I have not had the opportunity of talking with many Naval Surgeons on this subject, but those with whom I have talked, not only coincided with me as to the necessity of some more perfect water test, but expressed their belief in the practicability of the Wanklyn process on board ship, and the convenience of the apparatus I have described.
Note.
Since writing the foregoing, I have had the opportunity, at the laboratory of the Torpedo Station, of trying some experiments with the oxygen process, as described by Dr. Tidy. The results were fairly satisfactory, but upon trial, the method does not appear to me any better adapted to use on shipboard than it did on first reading. It requires for a determination, at least, four hours, and I do not see how the time can be reduced.
H. E.
Passed-Ass't Surgeon Corwin. I consider the plan proposed by the lecturer, for testing water, to be a step in advance of anything we now possess, and think there is no doubt as to its feasibility on ship board, the only objection being the time necessary for the determination. Time is here a matter of great importance. When the tests are to be made the medical officer is generally hurried, the water boat often coming alongside when the stores are coming in, and the decision is quickly required. I think at least an hour would be needed to do it properly. There could be a great saving of time however, if a standard of color were selected for comparison. For instance, a solution of potash bichromate or other coloring matter in 50 c. c. distilled water, of such strength that it should equal in depth of color that produced by a dangerous proportion of free or albuminoid ammonia with Nessler solution in the same bulk of liquid. The strength of such a color standard could quickly be ascertained by experiment and it could then be kept on hand, or prepared in a moment when wanted.
Two test tubes of equal size should be tilled, one with the color standard, and the second with the Nesslerised distillate. When the latter equals or exceeds in depth of color, the standard, the water must be rejected, when lighter in shade it may be accepted. This procedure may be objected to as not scientific, but there is no reason why the examiner, after passing upon the question of accepting or rejecting the water, should not be required to continue the experiment to the exact determination of organic impurity and keep a record of the results.
A good light is very necessary to distinguish the differences in intensity of color upon which the determination depends. It seems to me that the process is desirable and can be utilized; the reagents are simple and easily prepared, and it would prove an exceedingly useful method.
Prof. Munroe. The service is under great obligations to Lt. Comdr. Elmer for seeking to introduce into use Wanklyn's method. It is now well known to water analysts and among the many methods that have been devised and suggested during the last few years in which so much attention has been given by analysts and hygienists to the contaminations in potable water this method has met with the greatest favor and is quite extensively used. I can speak from personal experience as to the accuracy with which it will reveal the presence of ammonia and albuminoids in water and the ease with which it may be employed, as I have frequently used it in the examination of potable water. It must be borne in mind that this process does not supplant those now used by the medical officers; it merely supplements them. The total solids and chlorides must be determined as before; so the examination will occupy a longer time than heretofore. There is one objection that is urged against the Wanklyn process. It is said to prove too much and to condemn some waters which contain vegetable albuminoids which are not dangerous to health. This however is a point for the doctors to settle; the chemist simply proves the presence or absence of the albuminoidal substances. It is unfortunate for the service when a harmless natural water is condemned; for although there may be a plentiful supply of distilled water for use it is not so valuable as the natural water, since the latter contains certain salts and gases in solution which render it more palatable and which no doubt play a useful part in the animal economy. We try to reach this result by aerating our distilled water and I understand that in the Russian service they have issued a saline mixture to be added to the distilled water. It seems to me that it would assist our medical officers in deciding as to fitness of a water if they were directed to examine the source of the supply. They could then judge of the liability to contamination and whether the organic impurities were such as would prove dangerous to health. It would in many cases render an examination unnecessary by revealing the presence of stables etc. near the source of supply.
Passed-Ass't Surgeon Corwin. It certainly is advantageous to examine the source of supply, but it is not always practicable.
Passed-Ass't Eng. Kafer. It is a case in point to mention that since the China fleet suffered so severely from cholera, none but distilled water has been used on board the ships, and with beneficial results.
Passed Ass't Eng. Manning. The water which was extensively used in the North Atlantic Blockading Squadron, and which was generally preferred, was Juniper water from the Dismal Swamp. This would certainly have been condemned by this process, as it contained a great deal of vegetable matter, but it really was not objectionable.
Passed-Ass't Surgeon Corwin. I can understand that organic matter may exist in water, but, at the same time, its injurious effect be neutralized by the presence of some other principles, as in the case of the Juniper water.
The Chairman. I think the lecturer has taken a good step in bringing to notice this process and in making experiments to demonstrate the possibility of its use on board ship. From my experience as Executive Officer, I must agree with Dr. Corwin, that in a great many cases, it will take too much time. When the water boat comes along side, and the water must be taken in without delay, as frequently happens, it would take too long. In such a case the ordinary tests for salts would have to be used. With regard to examining the source, in those parts of the world not frequently visited by men-of-war, it would be an excellent idea, but at the ports most frequently visited the character of the water is generally pretty well known. I think the subject worthy of serious consideration, and I am sure all will agree with me in returning thanks to the lecturer for the pains he has taken in developing a very useful subject.